"Kay" wrote in message
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In article , Tumbleweed
thisaccountneverr
writes

"Kay" wrote in message
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In article , BAC
writes

"Kay" wrote in message
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In article , Franz Heymann
notfranz.
writes


It would be unwise for a pragmatist like me to say yes or no
to such a
possible false generalisation.
There are circumstances where I would be prepared to
participate in
the eradication of some species in certain places for the
sake of
humans, or domesticated animals, for example

Prickly pears for the sake of grazing field
The common cold virus
Malaria-carrying mosquitoes
Bracken in the Lake District
Hedgehogs in N Uist and Benbecula
Cats on Marion Island

Well, out of that lot, nos 1, 5 and 6 could be regarded as
putting
things right after introduction of species to places where
they don't
belong,

What do you mean by 'places where they don't belong'?

They didn't get there without human intervention.

Whether it "didnt belong there' is a human value judgement. Had, in
pre-human times, a chance event carried prickly pear seed to Oz,
and it had
become established, presumably you'd now be saying it did 'belong
there'?


It wouldn't have arrived there as a result of human activity. OK,
you
can say that it's irrelevant which species brought it there -
whether it
came on a duck's foot or in a human's hand baggage, for example, but
what this discussion is leading me to believe is that there is a
quantitative difference between us and other species - we do things
more
purposefully and on a larger scale, and therefore have a larger
effect.

Had Opuntia arrived in Oz as chance seeds in pre-human times, they
would
have established more slowly, other things would have evolved around
them. They would not have become the problem that they did.

Oh yes? For all practical purposes every piece of Opuntia which lands
on the ground roots. My father once established an Opuntia hedge
(believe it or not!) by cutting the "leaves" into four pieces each and
inserting each into the bare ground. The bulk of them rooted. Within
a couple of years we had more prickly pears than we could eat or sell
at the village auction market.

Franz